1) Field of the Invention
This invention relates to a mass spectrometry interface, a mass spectrometer and a mass spectrometry, more particularly to a mass spectrometry interface, a mass spectrometer and a mass spectrometry preferably usable for a mass spectrometry of a liquid sample, a liquid chromatograph, or a biological sample and an ionization spectroscopic analysis
2) Description of the Prior Art
Conventionally, a Matrix-Assisted Laser Deposition Ionization (MALDI) method or an electro spray method is employed for measuring a mass spectrum of a nonvolatile large mass molecule, and thus, the mass spectrum measuring technique is being widely applied for chemical fields or biological fields.
In the MALDI method, for enhancing the ionization of a dissolved substance to be analyzed in its mass, a large amount of matrix reagent is added into the sample solution incorporating the dissolved substance, and then, the thus obtained liquid sample is dropped onto a given plate to be evaporated and crystallized. Then, the plate is introduced into a mass spectrometer and irradiated by a laser beam to ionize the dissolved substance for its mass spectrometry.
In the electro spray method, a high voltage is applied to a nozzle to emit the liquid sample incorporating the dissolved substance, and thereby, the solvent of the liquid sample is desorbed and the dissolved substance is ionized. Then, the ionized dissolved substance is directly introduced into a mass spectrometer to be analyzed in its mass.
In the above electro splay method, an electrolyte is added to the liquid sample in order to enhance the ionization of the dissolved substance. Moreover, methanol, acetinitrile or the like to destroy the structure of a water is incorporated in the liquid sample for enhancing the desorption.
However, in the MALDI method, the liquid sample incorporating the dissolved substance may be often denaturalized due to much matrix reagent. Therefore, the MALDI method can not be applied for a liquid sample chemically changeable in short time and a long time-continuous measurement such as a mass spectrometry of a liquid chromatograph.
The electro spray method can not be also applied for the chemically changeable liquid sample and the long time-continuous measurement due to the denature of the liquid sample through the high voltage application. Moreover, if it is attempted that the denature of the liquid sample is prevented, the kind of the usable solvent is restricted. And then, if an associative solvent is employed in order to prevent the denature of the liquid sample, the clusters generated from the solvent molecules adheres to the solute species, and thus, the noises due to the clusters are superimposed on the mass spectrometry results of the dissolved substance.
It is an object of the present invention to provide a new mass spectrometer and mass spectrometry without the above matters.
For achieving the above object, the first invention relates to a mass spectrometry interface to constitute a mass spectrometer which comprises a vacuum chamber with a laser beam inlet, a metallic rotation-translation drum installed in the vacuum chamber, a sample supplying nozzle to emit and stabilize a liquid sample incorporating a dissolved substance to be analyzed in its mass for and onto the rotation-translation drum, and a laser source to irradiate a laser beam onto the dissolved substance from the laser beam inlet and to ionize the dissolved substance.
The second invention relates to a mass spectrometer to directly achieve the above object which comprises the above mass spectrometry interface or the following preferred mass spectrometry interface, an ion accelerating electrode part, and an mass spectrometry part.
Moreover, the third invention relates to a mass spectrometry using the above mass spectrometry interface or the mass spectrometer, comprising the steps of:
evacuating up to a given vacuum degree the interior of a vacuum chamber of a mass spectrometry interface constituting a mass spectrometer,
emitting a liquid sample incorporating a dissolved substance to be analyzed in its mass for a rotation-translation drum from a sample supplying nozzle of the mass spectrometry interface and thereby, stabilizing the dissolved substance on the rotation-translation drum, and
irradiating a laser beam for the stabilized dissolved substance from a laser source of the mass spectrometry interface via a laser beam inlet formed at the vacuum chamber and thereby, ionizing the dissolved substance.
According to the first through third inventions, only the dissolved substance to be analyzed in its mass is isolated on the metallic rotation-translation drum installed in the vacuum chamber, and a laser beam is directly irradiated on the deposited substance. Therefore, the substance isolated on the metal surface is ionized at high efficiency, and thus, an extreme high sensitive and efficient mass spectrometry can be performed.
The dissolved substance can fixed continuously as a long spiral belt on the rotation-translation drum. Therefore, the mass spectrometer and mass spectrometry of the present invention can be preferably employed for a long time-continuous measurement such as a mass spectrometry of a liquid chromatograph.
Therefore, much matrix reagent is not required, different from the MALDI method, and a high voltage is not also required, different from the electro-spray method. As a result, the denature of the liquid sample can be prevented, and the noises due to the clusters can be also prevented.